1. Field of the Invention
The present invention relates to a lever apparatus suitable for seat lifters for automobiles.
2. Background Art
Automobiles are often equipped with seat lifters which enable adjustment of the height of seats so as to accommodate the position of drivers with respect to the steeling wheel. Seat lifters generally comprise an elevating mechanism such as a parallel link or a pantograph that supports a seat on a floor, which elevates the seat. The elevating mechanism generally operates by rotating a driving shaft which is equipped therein. Handles have been widely used as an operating device for rotating the driving shaft. The handle-type operating device directly rotates a gear which is directly connected to the driving shaft, so that the structure thereof can be simple. However, the handle-type operating device requires a large operating force, and this does not allow easy operation.
Therefore, recently, lever-type operating devices have been widely used instead of the handle-type operating devices. The lever-type operating device rotates a driving shaft of an elevating mechanism by operating a lever upward or downward. U.S. Pat. No. 5,865,285 proposes a lever apparatus having a lever which is urged in to a neutral position. When the lever is moved, the action thereof is transmitted to a driving shaft via a gear. When the lever is released, it returns to the neutral position. The transmitting member for transmitting the operating movement of the lever consists of a latch which engages with the gear only when the lever is moved upward, and another latch which engages with the gear only when the lever is moved downward. Each latch serves as a one way ratchet, and the engagement of the latch with the gear changes according to the direction of the operation of the lever.
The above-mentioned lever apparatus must have at least two latches for transmitting the upward or downward operating movement of the lever to the gear. Therefore, the apparatus may have a large number of parts and be complicated, and problems therefore readily occur.
An object of the invention is to provide a lever apparatus which can reduce the number of parts and which can be simplified, and the reliability thereof can therefore be improved.
The invention provides a lever apparatus for operating a member, the apparatus comprising: a supporting member; a gear rotatably supported by the supporting member around a rotation shaft and connected to the member; a lever coaxially rotatably with the rotation shaft in a normal direction and in a reverse direction from a neutral position thereof within a predetermined angle; a return spring for returning the lever to the neutral position; a latch rotatably supported by the lever around a latch shaft and transmitting a rotation of the lever to the gear and providing a torque to the gear in the normal direction or in the reverse direction according to the direction of the lever; and an engaging shaft disposed between the latch and the supporting member. The engaging shaft engages the latch with the supporting member when the lever is rotated in the predetermined angle. When the lever is further rotated from the condition in which the latch engages with the supporting member via the engaging shaft, the latch is rotated around the engaging shaft by the latch shaft as a force point, so that engagement of the latch with respect to the gear is changed to a condition in which the gear is rotated in the normal direction or a condition in which the gear is rotated in the reverse direction.
According to the invention, the operated movement of the lever is transmitted to the gear connected to the member via the latch. The engagement of the latch with respect to the gear is changed to the condition in which the gear is rotated in the normal direction or the condition in which the gear is rotated in the reverse direction by the engagement of the engaging shaft with the supporting member. According to the invention, one latch enables the change of the normal rotation or reverse rotation of the gear, and the number of the parts can be relatively reduced and the construction thereof can be simple.